If you are FirstNet, a State, or a procurement official you are probably well aware that LTE has a limited amount of potential vendors. In the North American market we have Alcatel-Lucent, Ericsson, NSN (soon to be Nokia), Huawei and IP Wireless with GD. Let me break it down to the real players. First, Huawei is out, probably due to some type of overreaching threat of spy activity that would tap into all our phone lines and data calls to track what we are doing….or am I talking about the NSA? Doesn’t matter they are out. If we look at the remaining players three of them have real carrier deployments of LTE and make up the bulk of the worlds LTE deployments. IP Wireless does not have that footprint. It doesn’t mean somebody won’t roll out IP Wireless and given the four stages of a relationship I wish that willing party the best in their exploratory phase of such a young relationship. Thats always the best part of the relationship — lots of touching, feelings, and kissing….off topic sorry. We do have other makers of LTE, such as Fujitsu, but they seem to have an issue with leaving their own mainland.
Out of the main providers on the table — ALU, Ericsson and NSN — we have to look at the design of the solutions and whats best for this particular case. At the base of that comparison is the terms FDD and TDD. I’m not going to get technical on you here but you need to understand the TDD stands for “Time Division Duplex” and FDD stands for “Frequency Division Duplex”. If you insist on having the technical details then just google it. The main thing you need to know is that the traditional telephone networks, since the Bell days, were built on “Time Division Multiplexing” and is better known as “voice” or “telco” networks”. The entire cloud of the Internet was based on “Frequency Division Multiplexing” or better referred to as data or packet networks.
The introduction of wireless started on the TDM side of the house in direct support of Voice. Around the same time certain ventures starting exploring the use of such things as Wifi which ultimately created something called OFDM (Orthogonal Frequency Division Multiplexing). Got to love the complex terms. Makes me feel smart. Anyway OFDM became the basis for WiMax and LTE, but in this case the carrier market chose LTE over WiMax due specifically to the reason that LTE is better suited to accommodate the vast amounts of TDM infrastructure the carriers own and have owned since their creation. As it stands today 99% of the entire worlds carrier market has chosen LTE. It doesn’t matter if you think WiMax may be better…..Betamax was better than VHS.
Then came along the terms FDD versus TDD in the current realm of available LTE vendors. In layman’s terms what is the easiest way to explain which of the platforms is best suited for FirstNet? Well FirstNet doesn’t have the burden of an installed base of old TDM architectures that were designed to support voice and voice only, so why install TDD. The better choice is FDD!
The FDD solution was designed and made for the next step in the wireless networking world, which was the leap beyond small 32-bit voice packet architectures and onto the much bigger 64–1600 bit data packet architectures. The bigger packet sizes accommodate for more efficiency in data packet transmissions. Being that there is so many packets its better to take the large bus to school as opposed to the short small bus. As I have always said size does matter. Being that the majority of all the traffic on the FirstNet architecture will be data, then why would we consider deploying an architecture to support voice when voice isn’t our main reason for the network? Unless of course your business plan calls for a full-out connection and relationship with the national carriers to provide you your services — I’m referring to the FirstNet model. What better than to tie the entire Public Safety data requirements to an already established voice architecture that isn’t optimized for our needs! Now it may be me just stepping out of the box here, but wouldn’t it be inventive to deploy a data network for our data needs?
The best way to explain FD-LTE and TD-LTE is that FD-LTE is a router based network and the TD-LTE is a switch based network. Routers were made for larger data packets and switches were designed for smaller voice packets. The only time this really will really have an impact is if you are really pushing the bandwidth limits of your network; enough to where you have to start looking at efficiencies of use. Traditional TDM architectures carry a 30% overhead on every packet — that’s like taking a trip with a fully packed roll-aboard suitcase, plus an full packed computer bag, then adding another fully packed computer bag. It just becomes another financially impacted and non-efficient way of carrying your crap. It’s easier just to take two roll-aboard suitcases.
Being that the first iteration of the LTE deployments will have bandwidth 300 times that of the current data requirements of Public Safety gives us a little breathing room. But in the end their is only one real LTE vendor that properly aligns with the LTE based data packet architecture — NSN….who would have thought! So if you aren’t considering NSN for your solution then you may have been duped down a path that best supports the commercial carrier market than your own private data needs. Hopefully this explains why Voice Over LTE doesn’t exist today (as you would expect) — it’s because the carriers don’t need it. They make all their main revenue from their traditional business of assets which are all based on TDM telco voice services and designed for that means…why change to this thing called data? Seems so archaic. (sarcasm)
Just some guy and a blog…..